Model-Based Testing of the Gorums Framework for Fault-Tolerant Distributed Systems

摘要

Data replication is a central mechanism for the engineering of fault-tolerant distributed systems, and is used in the realization of most cloud computing services. This paper explores the use of Coloured Petri Nets (CPNs) for model-based testing of quorum-based distributed systems. We have developed an approach to model-based testing of fault-tolerant services implemented using the Go language and the Gorums framework. We show how a CPN model can be used to obtain both unit test cases for the quorum logic functions, and system level test cases consisting of quorum calls. The CPN model is also used to obtain the test oracles against which the result of running a test case can be compared. We demonstrate the application of our approach by considering an implementation of a distributed storage service on which we obtain 100% code coverage for the quorum functions, 96.7% statement coverage on the quorum calls, and 52.3% coverage on the Gorums framework. We demonstrate similar encouraging results also on a more complex Gorums-based implementation of the Paxos consensus protocol.